Extruded plastic hinge cover for terminal blocks

ABSTRACT

A snap-on hinge cover for a communications terminal block comprising an extruded plastic body having three longitudinally extending sections, the three sections being joined along longitudinally extending boundary regions to constitute a unitary structure. The outer longitudinal margins of the unitary structure having structure for snap-fitting onto the fanning strips of terminal block. Longitudinally hinge means is at one of said boundary regions. The hinge means is extruded along with components of plastic of the rest of the body, the hinge means having a resiliency which is high as compared to the resiliency of said body and constituting a memory which biases the hinged portion of the cover to an open position.

This application is a continuation, division, of application Ser. No.139,001, filed Dec. 29, 1987, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to new and useful improvements in acover of a type that fits onto a terminal block, the latter havingterminated communication wires therein.

The terminal blocks with which the present invention is concerned and inconnection with which the novel cover has been developed is of the typethat is usually formed of a molded plastic body having a number of rowsof holes into which electrical terminals are mounted. The terminals areelectrically insulated from one another to permit wire termination ofincoming and outgoing wires with which the terminal block is used. Theterminal block is furthermore formed along its opposed longitudinalmargins with fanning strips which fan out the wires that lead to andfrom the terminals within the block.

It is desireable that the terminals within the block be protectedagainst damage, and for this reason various attempts have been made toprovide protective covers. These attempts have included covers which aredifficult to install and remove except by destruction of the cover.Furthermore, the cover is normally injection molded and this factortends to make the costs of parts high.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly an object of the present invention is to provide a snap-onhinge cover for a communications terminal block that is an extrudedplastic part and is an inexpensive item to produce. The extrusiontechnique permits the use of two plastic materials in which one of theplastic materials is more resilient than the other, i.e. one of thematerials is for the main body of the cover and the other material iffor the cover hinge. Thus the resilient hinge material offers a longerlasting hinge action as well as facilitating latching of the cover inplace or biasing the cover to its full open position.

It is further object of this invention to provide a hinge cover of thetype stated which is extruded rather than injection molded, and istherefore less expensive to produce.

It is a more specific object of this invention to provide a snap-onhinge cover of the type stated in which the two plastic materials are ofthe same general type but differ in hardness and resiliency. The hingearea or areas are extruded with the two side by side layers which becomeinterally laminated in place during the extrusion process.

It is another object of this invention to provide a hinge cover of thetype stated in which the cover is designed for easy installation andremoval onto the terminal block without damage to terminals thereon.

It is a further object of this invention to provide a hinge cover of thetype stated in which the hinge has a "memory" therein brought about as aresult of the extrusion. This results in the hinge portion of the coverbeing biased outwardly and away from the block upon which the cover ismounted so as to facilitate access to the block by service personnel.

Accordingly, the cover comprises a plastic body having first, second,and third longitudinally extending sections, the second section beinglaterally intermediate the first and third sections, the three sectionsbeing joined along boundary regions, said first and third sectionshaving marginal regions spaced from said boundary regions, means at saidmarginal regions for snap-fitting said body onto opposed longitudinallyspaced fanning strips of a communications terminal block, longitudinallyextending hinge means at one of said boundary regions, said hinge beingformed as an extruded strip along with the extrusion of adjacentcomponents of plastic of said body and with said body being of apre-determined rigidity, said components having spaced adjacent edgesforming a gap and said hinge-forming extruded strip spanning said gapand having a resiliency which is high as compared to resiliency of saidbody and constituting a memory which biases the hinge portion of thecover to a pre-determined position.

In particular, resiliency of the hinge forming strip biases the hingeportion of the cover to an open position which is approximately 90degrees from the closed position. Furthermore, in the closed positionthe hinged portion of the cover engages the fanning strip by reason ofthe memory introduced into the extrusion, which is molded in the "coveropen" position.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a fragmentary perspective view of a snap-on hinge coverconstructed in accordance with and embodying the present invention andbeing shown mounted on a communications terminal block.

FIG. 2 is a front elevational view of the arrangement of FIG. 1 andshowing the hinge portion of the cover in two alternate positions,namely, open and closed;

FIG. 3 is an enlarged sectional view of a portion of FIG. 1 and with thehinge portion of the cover being shown projecting upwardly in accordancewith its normally molded position;

FIG. 4 is a fragmentary enlarged view of a portion of FIG. 2 at thelower left hand corner thereof; FIG. 5 is an enlarged fragmentarysectional view showing the hinged portion of the cover in the closedposition;

FIG. 6 is a perspective view partially in diagram form and showing theextrusion which forms part of the present invention; and

FIG. 7 is a fragmentary perspective view of a modified form of cover.

DETAILED DESCRIPTION

Referring now in more detail to the drawing, which illustrates apreferred embodiment of the present invention, 2 designates a one pieceplastic hinge cover for a communications terminal block of generallyconventional design. Suffice it to say that the terminal block 4 has anelongated plastic body 4 and is molded with a plurality of holes 6 whichare in a series of rows, and which are adapted to receive a series ofelectrical terminals 8. The terminals 8 are held within the block by aretaining plate 10 which makes a sliding tongue and groove connectionwith the main body portion of the block 4.

The terminals 8 are preferably of the multiple beam clip type in which awire is inserted between the adjacent beams of the clip, and theinsulation is sheared off of the wires by knife edges on the beam toestablish contact with the wire. Such clip type terminals are known inthe art and are shown, for example, in U.S. Pat. No. to Ayer 3,887,259.

The block 4 is also molded with fanning strips 12, 14 along oppositelongitudinal margins. These fanning strips accomodate the wires whichare connected to the terminals 8 and "fan out" therefrom. Generallyspeaking, the fanning strips in 14 are formed with a plurality ofoutwardly extremely posts having enlarged head portions 16.

The cover 2 is formed of extruded polyvinylchloride, a known andcommercially available resinous material. The plastic body of the coverhas first, second, and third longitudinally extending sections 18, 20,22, the three sections being joined along boundary regions 26, 28. Thefirst and third sections 18, 22 have marginal regions 30, 32 at whichare formed means for snap-fitting engagement of the cover 2 onto thefanning strips 12, 14 in overlying relationship to terminals 8.

The snap-on means at the margin 30 comprises a resilient hook 34 (FIG.4) which cooperates with a flange 36 to retain the nose of the hook 34underlying the enlarged head portion 16 of the fanning strip. At themargin 32 the cover is formed with a member 38 (FIG. 3) having a hook 40and an opposing shoulder 42. Opposite to the hook and shoulderarrangement and spaced therefrom is an additional shoulder 44 and thecompanion bead 46. The shoulder 44 and its associated bead together withthe hook 40 and its associated shoulder 42 cooperate to retain themember 38 in a snap-fitting relationship with the fanning strip.

As previously stated, the cover is extruded as a one piece member. Forthis purpose the cover is extruded in the "cover open" position shown inthe full lines in FIG. 2. The cover is comprised of two portions ofrigid plastic material and being joined by a hinge-forming strip 50.This hinge forming strip 50 therefore joins the adjacent hinge covercomponents 52, 54 (FIG. 3), spanning the gap 56 there between.

The material of the hinge strip is also formed of a polyvinylchlorideresin but with somewhat different properties than that of the resin usedfor the remainder of the cover. The cover is formed of a type 8700Aextrusion PVC. Such a material has a Rockwell R hardness of about 111.The hinge strip 50 is formed of a type 83718 extrusion compound and hasa Shore hardness of about 63 to 75. Both types of plastics, namely the8700A and the 83718 are sold under the trademark GEON and arecommercially available from the B.F. Goodrich Company, Akron, Ohio,U.S.A. In extruding the cover as showing full lines in FIG. 2, there isimparted into the strip 50 a memory or resiliency. Therefore, when thecover is swung down to its closed position, which is about 90 degreesfrom its open position, the spring potential of the strip 50 willenergize so that when the structure at the margin 30 snaps past thefanning strip and releases, the cover will be retained in a lockedposition under a spring pressure. Likewise, when access is desired tothe terminal block, release of the clip 34 (FIGS. 2 and 3) from thefanning strip will allow the cover to spring outwardly from the brokenline position shown in FIG. 3 to a full line position shown in FIG. 2where it will remain so as not to obstruct access to the wireconnections terminals in the block. It has been found that the desiredresiliency or memory present in the hinge strip 50, results when theextruding compound has a Shore hardness of about 63 to 75.

Extrusion is carried out by the extrusion dies which are conventional,as shown in FIG. 6. The two types of extrusion materials are pressedinto the dies 60, 62 and the hinge strip 50 is formed and is pressurelaminated onto the adjacent components 54, 52 of the more rigid plastic.

In modified form, the cover 2a is shown in FIG. 7. Here the marginalgripper portions 30a, 32a are configured so that these grippers 30a, 32alie outside of the main body of the cover rather than inside as in FIGS.1-6. Both grippers in FIG. 7 have hooks or nibs 90, 92 which serve toretain the cover in place. Other parts remain the same.

The invention is claimed as follows:
 1. A snap-on hinge cover for acommunications terminal block comprising a plastic body having first,second, and third longitudinally extending sections, the second sectionbeing laterally intermediate the first and third sections, and joinedthereto along boundary regions, said first and third sections havingmarginal regions spaced from said boundary regions, means at saidmarginal regions for snap-fitting and releasably locking said body ontoopposed longitudinally spaced fanning strips of a communicationsterminal block, longitudinally extending hinge means along one side ofsaid second section connecting adjacent marginal and boundary regions,said hinge means being formed as an extruded strip along with theextrusion of adjacent components of plastic of said body and with saidbody being of a predetermined rigidity, said components having spacedadjacent edges forming a gap and said hinge-forming extruded stripspanning said gap and having a resiliency which is high as compared tothe resiliency of said first, second, and third sections andconstituting a memory which biases the hinge portion of the cover to anopen position upon release of the snap-fitting engagement of themarginal region and fanning strip remote from the hinge means and withmaintenance of the snap-fitting engagement of the remote marginal regionand fanning strip under spring pressure of the hinge means with thecover in closed position.
 2. A snap-on hinge cover according to claim 1in which the plastic of the body has a Rockwell R hardness of about 111,and the hinge forming strip has a Shore hardness of about 63 to
 75. 3. Asnap-on cover according to claim 1 in which the resiliency of the hingeforming strip biases the hinge portion of the cover to an open positionwhich is approximately 90 degrees from the closed position.
 4. Incombination, a terminal block having a body with a plurality of rows ofopenings that receive electrical terminal clips and with said clipshaving means for termination of wires, said body also having fanningstrips on opposite sides of said clips and through which at least someof the terminated wires pass, and a protective cover for said clips,said cover having opposed margins with means interengaging said fanningstrips to retain the cover onto the block, and hinge forming springmeans on said cover for opening the cover to gain access to said clipterminals, said spring means having a memory in the form of resiliencythat biases the cover to an open position that facilitates access to theclip terminals, and also serves to bias the cover such that the coverwill be retained in a locked position under the pressure of said springin the closed position of the cover.
 5. A combination according to claim4 in which the hinge is in the form of a strip of extruded plastic thatjoins two sections of the cover.
 6. A combination according to claim 4in which the cover has open and closed positions 90 degrees apart.
 7. Asnap-on hinge cover according to claim 1 in which said first and thirdsections form side walls depending from said second section with one ofsaid side walls including the hinge means providing pivoting of thecover between the adjacent boundary and marginal regions.
 8. A snap-onhinge cover according to claim 1 in which the hinge means providespivoting of the cover along the boundary region between the second andthird sections.
 9. A snap-on hinge cover according to claim 1 in whichsaid first and third sections form side walls depending from said secondsection with one of said side walls including the hinge means above themarginal region thereof, and said marginal region having a supportmember extending laterally of the hinge means and carrying spaceddepending hook and shoulder means providing the fanning stripsnap-fitting engaging means.
 10. A snap-on hinge cover according toclaim 9 in which said support member extends laterally inwardly of thehinge means and is arcuate in shape to support the hook and shouldermeans therefrom.
 11. A snap-on hinge cover according to claim 9 in whichsaid support member extends laterally outwardly beyond the hinge meanslocated along the boundary region with the second section.